The misfitsThe genetic legacy of nomadism may be an inability to settl Tradução - The misfitsThe genetic legacy of nomadism may be an inability to settl Português como dizer

The misfitsThe genetic legacy of no

The misfits
The genetic legacy of nomadism may be an inability to settle

ABOUT one in 20 children (those under 18) have a group of symptoms that has come to be known as attention-deficit hyperactivity disorder (ADHD). About 60% of them carry those symptoms into adulthood. For what is, at root, a genetic phenomenon, that is a lot-yet many studies have shown that ADHD is indeed genetic and not, as was once suspected, the result of poor parenting. It is associated with particular variants of receptor molecules for neurotransmitters in the brain. A neurotransmitter is a chemical that carries messages between nerve cells and, in the case of ADHD, that chemical is often dopamine, which controls feelings of reward and pleasure. The suggestion is that people with ADHD are receiving positive neurological feedback for inappropriate behaviour. The surprise is that the variant receptors are still there. Natural selection might have been expected to purge them from the population unless they have some compensating benefit.

Of course, this analysis turns on the definition of "inappropriate". The main symptom of ADHD is impulsiveness. Sufferers have trouble concentrating on any task unless they receive constant feedback, stimulation and reward. They thus tend to flit from activity to activity. Adults with ADHD tend to perform poorly in modern society and are prone to addictive and compulsive behaviour. But might such people do well in different circumstances?

One hypothesis is that the behaviour associated with ADHD helps people, such as hunter-gatherers and pastoral nomads, who lead a peripatetic life. Since today's sedentary city dwellers are recently descended from such people, natural selection may not have had time to purge the genes that cause it.

Dan Eisenberg, of Northwestern University in Illinois, and his colleagues decided to test this by studying the Ariaal, a group of pastoral nomads who live in Kenya. The receptor Mr Eisenberg looked at was the 7R variant of a protein called DRD4. Previous work has shown that this variant is associated with novelty-seeking, food- and drug-cravings, and ADHD.

The team looked for 7R in two groups of Ariaal. One was still pastoral and nomadic. The other had recently settled down. As they report in this week's BMC Evolutionary Biology, they found that about a fifth of the population of both groups had the 7R version of DRD4. However, the consequences of this were very different. Among the nomads, who wander around northern Kenya herding cattle, camels, sheep and goats, those with 7R were better nourished than those without. The opposite was true of their settled relations: those with 7R were worse nourished than those without it.

How 7R causes this is not yet known. It may stem from behavioural differences or it may be that different versions of DRD4 have different effects on the way the body processes food. Nevertheless, this discovery fits past findings that 7R and a set of similar variants of DRD4, known collectively as "long alleles", are more common in migratory populations.

One suggestion is that long-distance migration selects for long alleles because they reward exploratory behaviour. This might be an advantage in migratory societies because it encourages people to hunt down resources when they constantly move through unfamiliar surroundings.

As for the Ariaal, there remains the question of why 7R-although it is apparently beneficial to a nomadic way of life-is found in only a fifth of the population. One possibility is that its effects are beneficial only when they are not universal, and some sort of equilibrium between variants emerges. A second is that the advantage is gained when 7R exists along with another version of DRD4 (the genes for the two variants having come from different parents). Unfortunately, the way Mr Eisenberg collected the data does not allow these hypotheses to be tested.

Either way, his research raises the question of whether people suffering from ADHD and conditions related to it, such as addiction, are misfits coping with a genetic legacy that was useful in the evolutionary past, but is now damaging. As society continues to diverge from that evolutionary past, the economic and social consequences of being such a misfit may become increasingly important.

Source: The Economist, June 14th, 2008 - pg. 98


Questão: 9 de 14

What is the main finding of the study that supports Dr. Eisenberg's hypothesis?


Nomadic Ariaal with 7R were better nourished than the Ariaal with 7R who had recently settled down.
Nomadic Ariaal with 7R were better nourished as they constantly moved through unfamiliar surroundings to find resources.
Nomadic Ariaal were better nourished because they knew how to hunt down resources.
One fifth of the population of both Ariaal groups had the 7R version of DRD4.
The genetic legacy of nomadism may be an inability to settle.


0/5000
De: -
Para: -
Resultados (Português) 1: [Cópia de]
Copiado!
The misfitsThe genetic legacy of nomadism may be an inability to settleABOUT one in 20 children (those under 18) have a group of symptoms that has come to be known as attention-deficit hyperactivity disorder (ADHD). About 60% of them carry those symptoms into adulthood. For what is, at root, a genetic phenomenon, that is a lot-yet many studies have shown that ADHD is indeed genetic and not, as was once suspected, the result of poor parenting. It is associated with particular variants of receptor molecules for neurotransmitters in the brain. A neurotransmitter is a chemical that carries messages between nerve cells and, in the case of ADHD, that chemical is often dopamine, which controls feelings of reward and pleasure. The suggestion is that people with ADHD are receiving positive neurological feedback for inappropriate behaviour. The surprise is that the variant receptors are still there. Natural selection might have been expected to purge them from the population unless they have some compensating benefit.Of course, this analysis turns on the definition of "inappropriate". The main symptom of ADHD is impulsiveness. Sufferers have trouble concentrating on any task unless they receive constant feedback, stimulation and reward. They thus tend to flit from activity to activity. Adults with ADHD tend to perform poorly in modern society and are prone to addictive and compulsive behaviour. But might such people do well in different circumstances?One hypothesis is that the behaviour associated with ADHD helps people, such as hunter-gatherers and pastoral nomads, who lead a peripatetic life. Since today's sedentary city dwellers are recently descended from such people, natural selection may not have had time to purge the genes that cause it.Dan Eisenberg, of Northwestern University in Illinois, and his colleagues decided to test this by studying the Ariaal, a group of pastoral nomads who live in Kenya. The receptor Mr Eisenberg looked at was the 7R variant of a protein called DRD4. Previous work has shown that this variant is associated with novelty-seeking, food- and drug-cravings, and ADHD.The team looked for 7R in two groups of Ariaal. One was still pastoral and nomadic. The other had recently settled down. As they report in this week's BMC Evolutionary Biology, they found that about a fifth of the population of both groups had the 7R version of DRD4. However, the consequences of this were very different. Among the nomads, who wander around northern Kenya herding cattle, camels, sheep and goats, those with 7R were better nourished than those without. The opposite was true of their settled relations: those with 7R were worse nourished than those without it.How 7R causes this is not yet known. It may stem from behavioural differences or it may be that different versions of DRD4 have different effects on the way the body processes food. Nevertheless, this discovery fits past findings that 7R and a set of similar variants of DRD4, known collectively as "long alleles", are more common in migratory populations.One suggestion is that long-distance migration selects for long alleles because they reward exploratory behaviour. This might be an advantage in migratory societies because it encourages people to hunt down resources when they constantly move through unfamiliar surroundings.As for the Ariaal, there remains the question of why 7R-although it is apparently beneficial to a nomadic way of life-is found in only a fifth of the population. One possibility is that its effects are beneficial only when they are not universal, and some sort of equilibrium between variants emerges. A second is that the advantage is gained when 7R exists along with another version of DRD4 (the genes for the two variants having come from different parents). Unfortunately, the way Mr Eisenberg collected the data does not allow these hypotheses to be tested.Either way, his research raises the question of whether people suffering from ADHD and conditions related to it, such as addiction, are misfits coping with a genetic legacy that was useful in the evolutionary past, but is now damaging. As society continues to diverge from that evolutionary past, the economic and social consequences of being such a misfit may become increasingly important.Source: The Economist, June 14th, 2008 - pg. 98Questão: 9 de 14What is the main finding of the study that supports Dr. Eisenberg's hypothesis? Nomadic Ariaal with 7R were better nourished than the Ariaal with 7R who had recently settled down. Nomadic Ariaal with 7R were better nourished as they constantly moved through unfamiliar surroundings to find resources. Nomadic Ariaal were better nourished because they knew how to hunt down resources. One fifth of the population of both Ariaal groups had the 7R version of DRD4. The genetic legacy of nomadism may be an inability to settle.
sendo traduzido, aguarde..
Resultados (Português) 2:[Cópia de]
Copiado!
Os desajustes
O legado genético do nomadismo pode ser uma incapacidade para resolver

cerca de um em 20 crianças (menores de 18 anos) têm um grupo de sintomas que veio a ser conhecido como transtorno de déficit de atenção e hiperatividade (TDAH). Cerca de 60% deles carregam esses sintomas na vida adulta. Pois o que é, no fundo, um fenômeno genético, que é a-lot ainda muitos estudos têm mostrado que o TDAH é realmente genética e não, como já foi suspeita, o resultado de pais pobres. Ela está associada com variantes particulares de moléculas de receptores para neurotransmissores no cérebro. Um neurotransmissor é um produto químico que transporta mensagens entre células nervosas e, no caso de ADHD, que é muitas vezes químico dopamina, que controla sensações de recompensa e prazer. A sugestão é que as pessoas com TDAH estão recebendo um feedback neurológico positivo para um comportamento inadequado. A surpresa é que os receptores variantes ainda estão lá. A seleção natural pode ter sido esperado para eliminá-los da população a menos que tenham algum benefício compensador.

Naturalmente, esta análise gira em torno da definição de "inadequado". O principal sintoma de TDAH é impulsividade. Os doentes têm dificuldade para se concentrar em qualquer tarefa a menos que recebam constante feedback, estímulo e recompensa. Eles, portanto, tendem a ficar circulando de atividade para atividade. Adultos com TDAH tendem a executar mal na sociedade moderna e são propensos a um comportamento viciante e compulsivo. Mas talvez essas pessoas fazem bem em circunstâncias diferentes?

Uma hipótese é que o comportamento associado com TDAH ajuda as pessoas, tais como caçadores-coletores nômades e pastorais, que levam uma vida itinerante. Desde os moradores da cidade sedentários de hoje foram recentemente descendente de tais pessoas, a seleção natural pode não ter tido tempo para purgar os genes que causam.

Dan Eisenberg, da Universidade Northwestern, em Illinois, e seus colegas decidiram testar esta estudando a ariaal, um grupo de pastores nómadas que vivem no Quênia. O receptor Sr. Eisenberg olhei foi a variante 7R de uma proteína chamada DRD4. Os trabalhos anteriores mostraram que esta variante está associada à busca de novidades, géneros alimentícios, medicamentos-ânsias, e ADHD.

A equipa procurou 7R em dois grupos de ariaal. Um ainda era pastoral e nômade. O outro tinha recentemente se estabeleceram. Como eles relatam na BMC Evolutionary Biology desta semana, eles descobriram que cerca de um quinto da população de ambos os grupos tiveram a versão 7R de DRD4. No entanto, as consequências desta foram muito diferentes. Entre os nômades, que vagueiam em torno norte do Quênia que agrupam o gado, camelos, ovelhas e cabras, aqueles com 7R eram mais bem nutridos do que aqueles sem. O oposto era verdade das suas relações se estabeleceram: aqueles com 7R eram piores nutridos do que aqueles sem ele.

Como 7R faz com que esse ainda não é conhecido. Ele pode decorrer de diferenças comportamentais ou pode ser que diferentes versões do DRD4 têm efeitos diferentes sobre a forma como o corpo processa os alimentos. No entanto, esta descoberta se encaixa descobertas anteriores que 7R e um conjunto de variantes semelhantes de DRD4, conhecidos coletivamente como "alelos longos", são mais comuns em populações migratórias.

Uma sugestão é que a migração de longa distância seleciona por longos alelos porque recompensar o comportamento exploratório . Isso pode ser uma vantagem em sociedades migratórias porque incentiva as pessoas a caçar recursos quando eles constantemente se move através ambientes desconhecidos.

Quanto ao ariaal, resta a questão de por que 7R-embora seja aparentemente benéfico para um modo de vida nómada-se encontrada em apenas um quinto da população. Uma possibilidade é que os seus efeitos são benéficas apenas quando eles não são universais, e algum tipo de equilíbrio entre as variantes emerge. A segunda é que a vantagem é obtida quando 7R existe juntamente com outra versão do DRD4 (os genes para as duas variantes tendo vindo de pais diferentes). Infelizmente, a forma como o Sr. Eisenberg recolheu os dados não permite que essas hipóteses a serem testadas.

De qualquer maneira, sua pesquisa levanta a questão de saber se as pessoas que sofrem de TDAH e condições relacionadas a ela, como a dependência, são desajustados lidar com um legado genético que foi útil no passado evolutivo, mas agora é prejudicial. Como a sociedade continua a divergir daquele passado evolutivo, as consequências económicas e sociais de ser tal desajuste pode tornar-se cada vez mais importante.

Fonte: The Economist, 14 de junho de 2008 - pg. 98


Questão: 9 de 14

? Qual é a principal conclusão do estudo que suporta a hipótese do Dr. Eisenberg


Nomadic ariaal com 7R eram mais bem nutridos do que o ariaal com 7R que recentemente estabeleceu-se.
Nomadic ariaal com 7R eram mais bem nutridos como eles constantemente mudou através de ambientes desconhecidos para encontrar recursos.
Nomadic ariaal estavam mais bem nutridos, porque eles sabiam como para caçar recursos.
um quinto da população de ambos os grupos ariaal tinha a versão 7R de DRD4.
o legado genético do nomadismo pode ser uma incapacidade de resolver.


sendo traduzido, aguarde..
 
Outras línguas
O apoio ferramenta de tradução: Africâner, Albanês, Alemão, Amárico, Armênio, Azerbaijano, Basco, Bengali, Bielo-russo, Birmanês, Bósnio, Búlgaro, Canarês, Catalão, Cazaque, Cebuano, Chicheua, Chinês, Chinês tradicional, Chona, Cingalês, Coreano, Corso, Crioulo haitiano, Croata, Curdo, Detectar idioma, Dinamarquês, Eslovaco, Esloveno, Espanhol, Esperanto, Estoniano, Filipino, Finlandês, Francês, Frísio, Galego, Galês, Gaélico escocês, Georgiano, Grego, Guzerate, Hauçá, Havaiano, Hebraico, Hindi, Hmong, Holandês, Húngaro, Igbo, Inglês, Ioruba, Irlandês, Islandês, Italiano, Iídiche, Japonês, Javanês, Khmer, Kinyarwanda, Klingon, Laosiano, Latim, Letão, Lituano, Luxemburguês, Macedônio, Malaiala, Malaio, Malgaxe, Maltês, Maori, Marata, Mongol, Nepalês, Norueguês, Oriá, Pachto, Persa, Polonês, Português, Punjabi, Quirguiz, Romeno, Russo, Samoano, Sessoto, Sindi, Somali, Suaíle, Sueco, Sundanês, Sérvio, Tadjique, Tailandês, Tcheco, Telugo, Turco, Turcomano, Tártaro, Tâmil, Ucraniano, Uigur, Urdu, Uzbeque, Vietnamita, Xhosa, Zulu, indonésio, Árabe, tradução para a língua.

Copyright ©2024 I Love Translation. All reserved.

E-mail: